It is often desirable for polymer producers, end-use manufacturers, additive suppliers, academicians, and others to establish quality control tests concerning anti-oxidant concentration or oxidative stability. Numerous techniques have been developed over the years to study the oxidative stability of polymers. Among various methods, chemiluminescence accompanying the thermal oxidation of polymers has been referred to by several authors (1-7). It was pointed out that the intensity of emitted light could be a convenient criterion for the estimation of thermal oxidative stability of polymers. The relationship EQU G.sub.t =K[ROOH].sub.t ( 1)
has been proposed where G.sub.t is time dependent light intensity, K is a constant and [ROOH].sub.t is hydroperoxide concentration (4).
In spite of the fact that the first publications concerning the possibility of using the chemiluminescence technique as the method for evaluating polymer thermal oxidative stability appeared about 20 years ago, no commercial installation of this kind has so far been offered. There are several reasons explaining this discrepancy:
1. Chemiluminescence technique is still largely a matter of discovering conditions under which the light emission relates to the properties of interest. PA1 2. The treatment of chemiluminescence results was based mainly on the comparison of maximum light intensities emitted by different samples and much additional important information has been missed. PA1 3. The chemiluminescence test requires many hours, especially when applied for the analysis of highly stabilized polymer systems. Thus, the productivity of the instruments used was low and could not satisfy the requirements.
It would therefore be desirable to have a method for the evaluation of chemiluminescence results which will provide various information (induction time, oxidation rate) concerning the thermal oxidative stability. It would also be advantageous to provide an instrument which would be able to analyze numerous polymer samples simultaneously.
Accordingly, it is an object of the present invention to provide a new chemiluminescence instrument and method having both the above mentioned features.